1. Field of the Invention
The present invention relates to an improved three-dimensional shape data processing technique. Particularly, the invention relates to a data processing technique for handing a plurality of two-dimensional outline data which is the base of generation of three-dimensional shape data for reproducing a solid object.
2. Description of the Related Art
As a method of generating three-dimensional shape data of an object to be measured three-dimensionally, there is a method utilizing a Shape From Silhouette (SFS) method. There will be simply explained below this method.
Firstly, an object is placed on a rotary stage, and while the rotary stage is being rotated once, the object is successively photographed by a photographing device such as a digital cameral fixed in a three-dimensional space so that a plurality of image data are obtained. Silhouette images are created by extracting outline shapes of the object from the obtained plural images, and three-dimensional data of the object are generated by the SFS method based on the silhouette images.
In the case where the three-dimensional data are created in such a manner, when the object is photographed by one photographing device, there is a case where the three-dimensional shape of the object cannot be sufficiently reproduced. For example, even if the object is successively photographed from a lateral direction, shape information about an upper portion or a lower portion of the object cannot sufficiently obtained.
In order to solve this problem, after the rotary stage is rotated so that an image group is once obtained, the direction of the object is changed so as to be rotated and an image group is obtained one more time. In this case, the shape information about the object which is insufficient in the first image group can be compensated by the second image group.
However, in the case where the direction of the object is changed and the image groups are obtained twice in the above manner, there arises a problem that the image group before the change and the image group after the change cannot be easily integrated. Namely, when the three-dimensional shape data of the object to be generated from the image group before the change are directly integrated with the three-dimensional shape data of the object from the image group after the change, a lot of labor and time are required for the integration.